Adjustments of the Circulatory System in Normal Dogs to Massive Transfusions

¹ From the Departments of Pharmacology and Physiology, Baylor University College of Medicine, and the University of Texas Dental School, Houston, Texas

On the basis of the amount of blood transfused in cubic centimeters per kilogram the dogs were arranged into five groups: group I, 0.0–49.0 cc/kg, group II, 50.0–99.0 cc/kg, group III, 100.0–149.0 cc/kg, group IV, 150.0– 199.0 cc/kg and group V, 200.0–249.0 cc/kg. The determinations made in each group were plasma volume, plasma proteins, hematocrit and hemoglobin. Plasma including protein escaped rapidly from the vascular system even with the smallest transfusion and in the last two groups the plasma lost exceeded that infused. Thus, any method of determining blood volume based on measurement of plasma volume must be in error. The loss of plasma protein became progressively greater as the amount of transfusion increased. The apparent increase in measured red cell volume over the expected in groups I, II and III was probably the result of loss of dye from the circulation, giving an overestimate of plasma and red cell volume. There was no evidence that cells leave the circulation until the transfusion volume became very large (groups IV, V) and hemorrhage supervened.

Note:
with the technical assistance of Stephanie Deavers, Jean Harrington and Carol M. Volkman